Research and invention skills. You can make a handy profit from alts being able to research 11 BPO’s at a time, BPO max-run copies, or from invention. Even if you have no use for the BPO’s or invented T2 BPC’s they can be sold at a much higher price than the original, unresearched BPO. Players are willing to pay quite a bit for BPO’s they don’t have to spend time on researching. Your alts could be doing this 24/7 in the background.